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* Add fused multiply-add instructionssheaf2023-05-111-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds eight new primops that fuse a multiplication and an addition or subtraction: - `{fmadd,fmsub,fnmadd,fnmsub}{Float,Double}#` fmadd x y z is x * y + z, computed with a single rounding step. This patch implements code generation for these primops in the following backends: - X86, AArch64 and PowerPC NCG, - LLVM - C WASM uses the C implementation. The primops are unsupported in the JavaScript backend. The following constant folding rules are also provided: - compute a * b + c when a, b, c are all literals, - x * y + 0 ==> x * y, - ±1 * y + z ==> z ± y and x * ±1 + z ==> z ± x. NB: the constant folding rules incorrectly handle signed zero. This is a known limitation with GHC's floating-point constant folding rules (#21227), which we hope to resolve in the future.
* Make `PosixSource.h` installed and under `rts/`John Ericson2021-08-091-1/+1
| | | | | | is used outside of the rts so we do this rather than just fish it out of the repo in ad-hoc way, in order to make packages in this repo more self-contained.
* Update Trac ticket URLs to point to GitLabRyan Scott2019-03-151-1/+1
| | | | | This moves all URL references to Trac tickets to their corresponding GitLab counterparts.
* Fix integer overflow when encoding doubles (Trac #15271)Fangyi Zhou2018-10-281-4/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: Ticket #15271 reports a case where 1e1000000000 is incorrectly converted to 0.0. After some investigation, I discovered the number is converted to rational correctly, but converting the ratio into a double introduced an error. Tracking down to how the conversion is done, I found the rts float implementation uses `ldexp`, whose signature is `double ldexp (double x, int exp);` The callsite passes an `I_` to the second argument, which is platform-dependent. On machines where `I_` is 64 bits and `int` is 32 bits, we observe integer overflow behaviour. Here is a mapping from rational to exponent with observations 1e646457008 -> 2147483645 (result = infinity, positive in int32) 1e646457009 -> 2147483648 (result = 0.0, overflow to negative in int32) 1e1000000000 -> 3321928042 (result = infinity, overflow to positive in int32) 1e1555550000 -> 5167425196 (result = 0.0, overflow to negative in int32) We fix this issue by comparing STG_INT_MIN/MAX and INT_MIN/MAX and bound the value appropriately. Test Plan: New test cases Reviewers: bgamari, erikd, simonmar Reviewed By: bgamari Subscribers: rwbarton, carter GHC Trac Issues: #15271 Differential Revision: https://phabricator.haskell.org/D5271
* fix bus error (misaligned data access) on SPARC in __decodeDouble_Int64Karel Gardas2015-03-221-3/+3
| | | | | | | | Reviewers: austin Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D749
* Restore exact old semantics of `decodeFloat`Herbert Valerio Riedel2014-11-191-0/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | `integer-gmp2` uses the new 64bit-based IEEE deconstructing primop introduced in b62bd5ecf3be421778e4835010b6b334e95c5a56. However, the returned values differ for exceptional IEEE values: Previous (expected) semantics: > decodeFloat (-1/0) (-4503599627370496,972) > decodeFloat (1/0) (4503599627370496,972) > decodeFloat (0/0) (-6755399441055744,972) Currently (broken) semantics: > decodeFloat (-1/0 :: Double) (-9223372036854775808,-53) > decodeFloat (1/0 :: Double) (-9223372036854775808,-53) > decodeFloat (0/0 :: Double) (-9223372036854775808,-53) This patch reverts to the old expected semantics. I plan to revisit the implementation during GHC 7.11 development. This should address #9810 Reviewed By: austin, ekmett, luite Differential Revision: https://phabricator.haskell.org/D486
* Revert "rts: add Emacs 'Local Variables' to every .c file"Simon Marlow2014-09-291-8/+0
| | | | This reverts commit 39b5c1cbd8950755de400933cecca7b8deb4ffcd.
* `M-x delete-trailing-whitespace` & `M-x untabify`Herbert Valerio Riedel2014-09-241-14/+14
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* Implement `decodeDouble_Int64#` primopHerbert Valerio Riedel2014-09-171-0/+18
| | | | | | | | | | | | | | | The existing `decodeDouble_2Int#` primop is rather inconvenient to use (and in fact is not even used by `integer-gmp`) as the mantissa is split into 3 components which would actually fit in an `Int64#` value. However, `decodeDouble_Int64#` is to be used by the new `integer-gmp2` re-implementation (see #9281). Moreover, `decodeDouble_2Int#` performs direct bit-wise operations on the IEEE representation which can be replaced by a combination of the portable standard C99 `scalbn(3)` and `frexp(3)` functions. Differential Revision: https://phabricator.haskell.org/D160
* rts: detabify/dewhitespace StgPrimFloat.cAustin Seipp2014-08-201-48/+48
| | | | Signed-off-by: Austin Seipp <austin@well-typed.com>
* rts: add Emacs 'Local Variables' to every .c fileAustin Seipp2014-07-281-0/+8
| | | | | | | | This will hopefully help ensure some basic consistency in the forward by overriding buffer variables. In particular, it sets the wrap length, the offset to 4, and turns off tabs. Signed-off-by: Austin Seipp <austin@well-typed.com>
* Remove unused __2Int_encodeDoubleIan Lynagh2013-05-191-23/+0
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* RTS tidyup sweep, first phaseSimon Marlow2009-08-021-249/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The first phase of this tidyup is focussed on the header files, and in particular making sure we are exposinng publicly exactly what we need to, and no more. - Rts.h now includes everything that the RTS exposes publicly, rather than a random subset of it. - Most of the public header files have moved into subdirectories, and many of them have been renamed. But clients should not need to include any of the other headers directly, just #include the main public headers: Rts.h, HsFFI.h, RtsAPI.h. - All the headers needed for via-C compilation have moved into the stg subdirectory, which is self-contained. Most of the headers for the rest of the RTS APIs have moved into the rts subdirectory. - I left MachDeps.h where it is, because it is so widely used in Haskell code. - I left a deprecated stub for RtsFlags.h in place. The flag structures are now exposed by Rts.h. - Various internal APIs are no longer exposed by public header files. - Various bits of dead code and declarations have been removed - More gcc warnings are turned on, and the RTS code is more warning-clean. - More source files #include "PosixSource.h", and hence only use standard POSIX (1003.1c-1995) interfaces. There is a lot more tidying up still to do, this is just the first pass. I also intend to standardise the names for external RTS APIs (e.g use the rts_ prefix consistently), and declare the internal APIs as hidden for shared libraries.
* Remove the implementation of gmp primops from the rtsDuncan Coutts2009-06-131-81/+0
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* Remove __encodeDouble and __encodeFloat from the rtsDuncan Coutts2009-06-111-44/+0
| | | | They now live in the integer-gmp package.
* Remove the unused remains of __decodeFloatIan Lynagh2009-06-021-49/+0
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* add (c) Lennart Augustsson (part of #740)Simon Marlow2008-09-081-0/+1
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* Fix conversions between Double/Float and simple-integerIan Lynagh2008-06-141-4/+32
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* Missing .0 on float constant.Don Stewart2008-05-011-1/+1
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* Replace C99 exp2f(32) call in __2Int_encodeDoubleDon Stewart2008-04-301-1/+1
| | | | | | | | with constant 4294967296. exp2f is a C99-ism not availabl everywhere. Replace it with its result. Helps building on OpenBSD>
* Add some more generic (en|de)code(Double|Float) codeIan Lynagh2008-04-171-0/+108
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* Cope with big endian float word order on little endian machinesIan Lynagh2006-11-201-1/+16
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* Reorganisation of the source treeSimon Marlow2006-04-071-0/+491
Most of the other users of the fptools build system have migrated to Cabal, and with the move to darcs we can now flatten the source tree without losing history, so here goes. The main change is that the ghc/ subdir is gone, and most of what it contained is now at the top level. The build system now makes no pretense at being multi-project, it is just the GHC build system. No doubt this will break many things, and there will be a period of instability while we fix the dependencies. A straightforward build should work, but I haven't yet fixed binary/source distributions. Changes to the Building Guide will follow, too.
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